I don't think it's particularly helpful towards new players to scare them away from custom games. While getting totally owned by arranged teams isn't particularly helpful, playing against human players is far more helpful than playing against bots (I still haven't played a single Pantheon/Skirmish where majority of players wouldn't be bots).
Sure, you can lose more often in Custom games, but you also learn a lot more. When a particularly nasty tactic (capping+caplocking enemy base portals?) is used against you, you know to be prepared against it next time, and can also use it yourself.
As for winning by using favor items, or just good items from shops, why not? Everybody has equal chances to buy items from shops, so even assuming there were some op items, everybody still hass access to same items. It makes no sense to cripple yourself by refusing to use certain items. Well, ye, should there be some really op items, I might avoid them partly out of some stubborness, partly because they would be fixed later, so not relying on them to begin with might be better on long term. But that's just me, there's nothing wrong using tools given to win, assuming they aren't exploits.
Favour items atm are a bit more problematic. Imo using them is fair, it doen't need too many games to get one. But still, players aren't equal at the start of a game, which is just not cool. There is a thread about unlocking all favor items elsewhere, anyway. But it's not like favour items are game breaking or mean autowin. If you don't have one, you just play a bit more carefully. Assuming favour points don't bug, as they tend to, it takes about five or six wins to unlock many useful favour items, and this is a team game, team can win even with one player lacking a favour item.
These are of course only my opinions, but still, I believe the original post is misleading new players.
Ouch, this became a real wall of text. Well, something to do while waiting for a game 
